JP6504120B2 - Developing device and image forming apparatus - Google Patents

Description

  The present invention relates to a developing device for developing an electrostatic latent image using toner, and an image forming apparatus including the developing device.

  In Patent Document 1, a flat cable is wound around a body of a toroidal core mounted on a printed circuit board, and both ends of the flat cable lead are electrically conductively bonded to the pattern of the printed circuit board. A toroidal coil is described in which the winding of the body of the toroidal core is configured. Thereby, it is going to comprise a coil using a flat cable (patent document 1: Claim 1, refer to FIG. 1).

Japanese Utility Model Application Publication No. 61-51715

  Some image forming apparatuses such as multifunction machines, copiers, printers, and facsimiles include a developing device that stores a developer including a magnetic carrier and a toner and develops an electrostatic latent image with the toner. In such an image forming apparatus, only toner is consumed along with printing. Eventually, the toner decreases (the toner concentration decreases) with respect to the ideal ratio of the magnetic carrier of the developer to the toner. In order to detect a decrease in toner concentration, a toner concentration sensor may be provided in the developing device. Based on the detection result, toner replenishment is performed.

  A coil may be used for the toner concentration sensor. When the ratio of the magnetic carrier changes with the consumption and replenishment of the toner, the magnetic permeability of the developer changes. For example, when the toner decreases and the ratio of magnetic carriers increases (when the magnetic permeability of the developer increases), the inductance value of the coil increases. Based on the change in the inductance value of the coil, the ratio of the magnetic carrier to the toner can be detected to determine whether the toner needs to be replenished.

  As the toner concentration sensor, a circuit that outputs a signal according to the current ratio of magnetic carrier to toner (toner concentration) is used. For example, a resonance circuit in which a capacitor is added to a coil is included in the toner concentration sensor. A change in coil inductance changes the resonant frequency. The toner concentration sensor outputs a signal according to the resonance frequency.

  Conventionally, a coil pattern substrate on which a coil pattern is printed is used as a coil of a toner concentration sensor. The coil pattern substrate is disposed outside and near the developing device. In order to suppress the resonance frequency (resonance frequency) low and reduce unnecessary radiation of radio waves, it is necessary to secure a certain degree of large inductance. In order to obtain a coil having a large inductance value, a multilayer substrate in which a plurality of substrates provided with a coil pattern are stacked may be used. However, multilayer substrates can be expensive to manufacture.

  In addition, when a metallic member having a high magnetic permeability such as iron is present near the coil, the output of the toner concentration sensor is influenced by the metallic member. It is necessary to separate the coil and the metal member to such an extent that no problem occurs in the output of the toner concentration sensor. In the case of using a flat cable as a coil, it is conceivable to increase the number of turns by using a wide (large number of conductors included) flat cable in order to secure the inductance. However, in recent years, miniaturization of the image forming apparatus including the developing device and the developing device has progressed, and the design of the periphery of the developing device is restricted. It is difficult to design no metal member in a wide range where there is no problem in the output signal of the toner concentration sensor centering on the coil of a wide flat cable. However, there is a problem that a coil with a large inductance can not be obtained by using a narrow flat cable.

  When the toroidal coil (coil of fixed closed magnetic path) described in Patent Document 1 is used for the toner concentration sensor, the toroidal coil and the substrate thereof are not provided outside the container of the developing device so that the developer does not contact directly. It must not be. Therefore, only a part of the toroidal coil can be brought close to the developer. Therefore, the toroidal coil described in Patent Document 1 can not accurately capture the change in the ratio of the magnetic carrier to the toner, and is not suitable as a coil for the toner concentration sensor. Moreover, the above problems can not be solved.

  SUMMARY OF THE INVENTION In view of the above problems, the present invention detects a toner concentration accurately by using a narrow flat cable so that a coil having a desired inductance value can be obtained inexpensively and easily.

  In order to achieve the above object, a developing device according to claim 1 includes a developing container, a first conveying member, a second conveying member, a developing roller, a toner density sensor, a flat cable, and a cable substrate. The developer container contains a developer containing a carrier and a toner, and is divided into a first section and a second section, and both ends of the first section and the second section in the longitudinal direction are the first section And it becomes a communication part which connects the end parts of said 2nd division, and a crevice is provided between the 1st division and the 2nd division inside the longitudinal direction rather than each said communication part. The first transport member is provided in the first section, and transports the developer while stirring the developer along the longitudinal direction of the developing container. The second transport member is provided in the second section, and transports the developer in the developer container while stirring in a direction opposite to the first transport member. The developing roller is rotatably supported by the developing container and carries a developer to be supplied to an image carrier on which an electrostatic latent image is formed. The toner concentration sensor is for detecting the toner concentration in the developer and includes a coil. The flat cable is wound as a plurality of turns around the part of the first section through the gap as the coil. The cable substrate is provided with a plurality of connectors, and patterns are wired. In the connector, one of the ends of the flat cable is inserted, and a plurality of connector terminals in contact with the ends of the conductors of the flat cable are provided. The cable substrate includes the conductors at one end of the flat cable and the conductors at the other end of the flat cable so that the flat cable connected to the connector forms one coil of the first section. It includes the pattern wired to connect.

  According to the present invention, a coil having a desired inductance value can be obtained inexpensively and simply by using a flat cable with a narrow width. Also, the toner concentration can be detected accurately.

FIG. 1 is a diagram illustrating an example of a printer according to an embodiment. FIG. 2 is a view showing an example of each image forming unit according to the embodiment. FIG. 6 is a view showing an example of a portion for supplying toner to each developing device according to the embodiment. FIG. 2 is a view showing an example of a toner concentration sensor according to the embodiment. It is a figure showing an example of LC oscillation circuit concerning an embodiment. It is sectional drawing of the horizontal direction of the image development apparatus 1 which concerns on embodiment. It is sectional drawing of the image development apparatus which concerns on embodiment in the AB direction of FIG. FIG. 7 is a cross-sectional view of the developing device according to the embodiment in the direction CD in FIG. It is a figure showing an example of the flat cable concerning an embodiment. It is a sectional view of a flat cable concerning an embodiment. It is a figure which shows an example of the state which wound the flat cable which concerns on embodiment as a coil. It is a figure showing an example of the cable substrate concerning an embodiment. It is a figure showing an example of the connector provided in the cable substrate concerning an embodiment. It is a figure showing an example of the hook concerning an embodiment. It is a figure showing an example of winding to the 1st section of a flat cable in a modification. It is a figure which shows an example of the cable board which concerns on a modification.

  Hereinafter, an embodiment of the present invention will be described with reference to FIGS. In the following description, a printer 100 (corresponding to an image forming apparatus) including the developing device 1 according to the present invention will be described as an example. However, each element of the configuration, arrangement, and the like described in the present embodiment does not limit the scope of the invention, and is merely an illustrative example.

(Outline of the image forming apparatus)
Next, an outline of the printer 100 according to the embodiment will be described based on FIG. FIG. 1 is a diagram illustrating an example of a printer 100 according to the embodiment.

  In the printer 100, a main control unit 2 is provided. The main control unit 2 controls the operation of the printer 100. The main control unit 2 includes a CPU 21 and an image processing unit 22. The CPU 21 performs control of each unit of the printer 100 and various arithmetic processing based on the programs and data stored in the storage unit 23. The image processing unit 22 performs necessary image processing such as density conversion, enlargement, reduction, and rotation based on data (data for printing) indicating print settings and print contents transmitted from the computer 200 and received by the communication unit 24. Apply to data.

  The storage unit 23 is a combination of a nonvolatile storage device such as a ROM and an HDD and a volatile storage device such as a RAM. The storage unit 23 stores various programs and data for controlling the printer 100, various data such as setting data, and image data.

  The printer 100 includes an operation panel 3. The operation panel 3 includes a state of the printer 100, various messages, a display panel for displaying various setting screens, and a plurality of hard keys for setting operation. The main control unit 2 controls the display of the operation panel 33. Further, the main control unit 2 recognizes the setting operation content of the operation panel 33 and controls the printer 100 according to the setting.

  The printer 100 also includes a printing unit 4. The printing unit 4 includes an engine control unit 40, a sheet feeding unit 4a, a conveyance unit 4b, an image forming unit 4c, an intermediate transfer unit 4d, and a fixing unit 4e. Further, in the printer 100, a plurality of motors 4f for rotating various rotating bodies included in the printing unit 4 are provided. The engine control unit 40 includes a CPU and a memory. The main control unit 2 provides the engine control unit 40 with data indicating the content of the print job such as a print instruction or image data. The engine control unit 40 actually operates the sheet feeding unit 4a, the conveyance unit 4b, the image forming unit 4c, the intermediate transfer unit 4d, the fixing unit 4e, and the motor 4f based on the instruction from the main control unit 2 and the given image data. To control printing related processing such as sheet feeding, sheet conveyance, toner image formation, transfer, fixing, toner density detection, and toner replenishment.

  The engine control unit 40 supplies sheets used for printing one by one to the sheet feeding unit 4a. The engine control unit 40 transports the sheet supplied to the transport unit 4 b. The engine control unit 40 forms a toner image on the image forming unit 4c. The image forming unit 4c includes a plurality of image forming units 41 (in FIG. 1, only one image forming unit 41 is shown for convenience). Specifically, a total of four image forming units 41 of black, cyan, yellow and magenta are provided. The intermediate transfer portion 4 d includes an intermediate transfer belt 42 (see FIG. 2) which receives the primary transfer of the toner image of each color formed by each image forming unit 41. The engine control unit 40 rotates the intermediate transfer belt 42 to primarily transfer the toner image formed by the image forming unit 4c to the intermediate transfer belt 42, and intermediately transfers the secondary transfer of the toner image onto the sheet to be conveyed. Make it part 4d. The engine control unit 40 fixes the toner image transferred to the sheet on the fixing unit 4 e.

(Each image forming unit 41)
Next, an example of each image forming unit 41 according to the embodiment will be described with reference to FIG. FIG. 2 is a view showing an example of each image forming unit 41 according to the embodiment.

  The image forming unit 4 c includes image forming units 41 for four colors. The image forming unit 4c also includes an exposure device 44 that scans and exposes each photosensitive drum 43 included in each image forming unit 41 with a laser beam (see FIG. 1). Each image forming unit 41 is different in the color of the toner image to be formed, but all have the same configuration. Therefore, hereinafter, one image forming unit 41 will be described as an example. Other image forming units 41 can be similarly described.

  As shown in FIG. 2, the image forming unit 41 includes a photosensitive drum 43, a charging device 45, a developing device 1, a cleaning device 46, and a charge removing device 47. The photosensitive drum 43 receives the driving force of the motor 4f and rotates at a predetermined peripheral speed. The charging device 45 charges the surface of the photosensitive drum 43 at a constant potential. The exposure device 44 is disposed below each image forming unit 41. The exposure device 44 uses an optical system member such as a semiconductor laser device (laser diode), a polygon mirror, a polygon motor, an fθ lens, and a mirror inside, and an optical signal based on an image signal obtained by color separation of image data ( A laser beam (shown by a broken line in FIG. 2) is applied to the charged photosensitive drum 43 to scan and expose the photosensitive drum 43. As a result, an electrostatic latent image combined with the image data is formed on the circumferential surface of the photosensitive drum 43.

  The developing device 1 includes a first conveying member 11, a second conveying member 12, and a developing roller 13. Further, the developing device 1 accommodates a developer containing a magnetic carrier and a toner in a housing (developing container 10). The magnetic carrier is powdery and is a ferromagnetic material such as ferrite. The developer contains toner of a color according to the formation color of the image forming unit 41. Each developing device 1 is connected to a toner container 48 (see FIG. 3) that contains the toner of the corresponding color. As the toner is consumed, toner is replenished from the toner container 48 to the developing device 1.

  The cleaning device 46 cleans the photosensitive drum 43. The cleaning device 46 extends in the axial direction of the photosensitive drum 43 and rubs the surface of the photosensitive drum 43 to remove residual toner and the like. Further, the charge removing device 47 applies light to the photosensitive drum 43 to perform charge removal.

(Toner supply)
Next, replenishment of toner to each developing device 1 will be described with reference to FIG. FIG. 3 is a view showing an example of a portion for supplying toner to each developing device 1 according to the embodiment. In FIG. 3, the flow of toner is indicated by a white arrow.

  The printer 100 is provided with a toner container 48 for storing toner for replenishment, and a replenishment mechanism 49 for transferring toner from the toner container 48 to the developing device 1 for replenishment, for each color of toner. The magnetic carrier may also be reduced little by little with printing, and a small amount of magnetic carrier may be mixed with the toner. A total of four toner containers 48 of black, cyan, yellow, and magenta are attached to the printer 100. Each toner container 48 is replaceable and replaced when empty. Each supply mechanism 49 includes a conveying screw (not shown) for feeding the toner from the toner container 48 toward the developing device 1, a motor 4f for rotating the conveying screw, and a gear (not shown). One replenishing mechanism 49 is provided for the toner container 48 and the developing device 1.

  Further, each developing device 1 is provided with a toner concentration sensor 5 for detecting the toner concentration in the developing device 1 (the ratio of the magnetic carrier in the developer to the toner). At the time of predetermined concentration detection, the engine control unit 40 determines whether toner replenishment is necessary based on the output of the toner concentration sensor 5. The predetermined density detection is performed, for example, when the main power is turned on, when returning to the normal mode, during printing, before the start of the print job, or when the print job is ended.

(Toner concentration sensor 5)
Next, the toner concentration sensor 5 according to the embodiment will be described with reference to FIGS. 4 and 5. FIG. 4 is a view showing an example of the toner concentration sensor 5 according to the embodiment. FIG. 5 is a diagram showing an example of the LC oscillation circuit 50 according to the embodiment.

  As shown in FIG. 4, the toner concentration sensor 5 includes an LC oscillation circuit 50. The LC oscillation circuit 50 includes a coil 6 using a flat cable 7. The output of the toner concentration sensor 5 (LC oscillation circuit 50) is input to the engine control unit 40. The engine control unit 40 detects the ratio of the magnetic carrier to the toner based on the resonance frequency of the LC oscillation circuit 50, and determines whether the toner should be replenished.

  FIG. 5 shows an example of the LC oscillation circuit 50. The LC oscillation circuit 50 includes a coil 6, a first resistor R1, a second resistor R2, a first capacitor C1, a second capacitor C2, a first inverter INV1, and a second inverter INV2. The LC oscillation circuit 50 of FIG. 5 is a kind of Colpitts oscillation circuit.

  One terminal of the coil 6 is connected to one end of the first capacitor C1, the input terminal of the first inverter INV1, and one end of the first resistor R1. The other terminal of the coil 6 is connected to one end of a second capacitor C2 and one end of a second resistor R2. The other end of the first capacitor C1 and the other end of the second capacitor C2 are connected to the ground. The output terminal of the first inverter INV1 is connected to the other end of the first resistor R1, the other end of the second resistor R2, and the input terminal of the second inverter INV2. The output of the second inverter INV2 is input to the engine control unit 40.

By the second resistor R2 of the negative feedback circuit, the first capacitor C1, the second capacitor C2 and the coil 6, the phase is about 180 degrees, and the negative feedback oscillates as a positive feedback. The resonant frequency is f = 1 / 2π ((LC) ^1/2 ). A sine wave is input to the second inverter INV2. The second inverter INV2 converts the input sine wave into a rectangular wave.

  The inductance of the coil 6 changes according to the ratio of the magnetic carrier of the developer to the toner. When the toner is consumed and the proportion of magnetic carriers in the developer increases, the inductance of the coil 6 increases. As the ratio (density) of the magnetic carrier in the developer increases (as the amount of toner decreases), the denominator in the above equation increases, and the frequency (resonance frequency) of the output signal of the LC oscillation circuit 50 (second inverter INV2) decreases. Become. On the other hand, since the denominator of the above equation decreases as the amount of toner in the developer decreases, the frequency of the output signal of the LC oscillation circuit 50 increases.

  The counter 40a (see FIG. 4) provided in the engine control unit 40 is a pulse of the output (rectangular wave) of the second inverter INV2 for a predetermined count period such as a period in which each conveyance member rotates one or more times. Count the number. For example, the storage unit 23 stores density measurement data D1 whose reference value is the number of pulses in the count period when the ratio of the magnetic carrier to the toner is ideal (see FIG. 1).

  The engine control unit 40 compares the count value of the counter 40a with the reference value, and when it is less than the reference value (when the resonance frequency is smaller than when the ratio of the magnetic carrier to the toner is ideal), the toner Decide to supply In other words, based on the output of the toner concentration sensor 5, the engine control unit 40 should detect the color in which the toner is low with respect to the ideal ratio of magnetic carrier to toner, and supply the toner of the detected color. I will judge.

  The engine control unit 40 operates the replenishment mechanism 49 corresponding to the developing device 1 that has determined that the toner should be replenished. The engine control unit 40 causes the replenishment mechanism 49 to replenish toner until the number of pulses in the count period becomes equal to or greater than the reference value (until the ratio of the magnetic carrier to the toner becomes ideal), and then the replenishment mechanism 49 Stop.

(Developing device 1)
Next, the developing device 1 according to the embodiment will be described with reference to FIGS. FIG. 6 is a horizontal sectional view of the developing device 1 according to the embodiment. FIG. 7 is a cross-sectional view of the developing device 1 according to the embodiment in the AB direction of FIG. FIG. 8 is a cross-sectional view of the developing device 1 according to the embodiment in the C-D direction of FIG.

  In the following description, the developing device 1 included in each image forming unit 41 will be described. The configuration and operation of the developing device 1 included in each image forming unit 41 are the same. Each developing device 1 can be described in the same manner.

  The developing device 1 includes a developing container 10 that contains a developer including a carrier and a toner. The developing container 10 is a housing (outer shell) of the developing device 1. The lower portion of the developer container 10 is divided into a first section 14 and a second section 15. The replenishment mechanism 49 supplies the toner to be replenished to the first section 14. FIG. 6 is a view of the developing device 1 as viewed from below, and is a cross-sectional view in which the portions of the first section 14 and the second section 15 of the developing device 1 are temporarily cut in the horizontal direction. As shown in FIG. 6, a gap 16 (hollow portion) is provided between the first section 14 (section for conveying the developer while stirring the developer) and the second section 15 (section for supplying the developer to the developing roller 13). Be

  The first transport member 11 is provided in one section (the first section 14), and the second transport member 12 is provided in the other section (the second section 15). A spiral blade 11 a is provided on the rotation shaft of the first conveyance member 11, and a spiral blade 12 a is provided on the rotation shaft of the second conveyance member 12. The first conveying member 11 and the second conveying member 12 are screws that rotate and convey the developer in the developing container 10 while stirring it along the longitudinal direction of the developing container 10. The toner is charged by friction due to stirring. The directions in which the first transport member 11 and the second transport member 12 transport the developer are different from each other (FIG. 6 illustrates an example of the transport direction of the developer). The second conveyance member 12 close to the developing roller 13 supplies the developer to the developing roller 13.

  Further, as shown in FIG. 6, at both end portions of each of the first section 14 and the second section 15 in the longitudinal direction, there is provided a communicating portion 17 for connecting the end sections of the first section 14 and the second section 15. . The developer reaching the end of the compartment flows into the next compartment through the communicating portion 17. The first conveying member 11 and the second conveying member 12 convey the developer while stirring it so that the developer circulates in the developing container 10.

  The developing roller 13 is disposed in the developing container 10 above the developing container 10 (second conveying member 12) (see FIGS. 7 and 8). The developing roller 13 is disposed to face the image carrier (photosensitive drum 43) on the opening side of the developing container 10. A predetermined interval is provided between the developing roller 13 and the photosensitive drum 43. The developing roller 13 carries a developer on the surface, and supplies toner to the photosensitive drum 43 in a region facing the photosensitive drum 43.

  The developing roller 13 includes a rotating cylindrical nonmagnetic developing sleeve 13a (see FIG. 7). The developing sleeve 13a includes a fixed magnet body (not shown) having a plurality of magnetic poles. As a fixed magnet body, a regulating pole (not shown) consisting of N poles, a transport pole (not shown) consisting of S poles, a main pole (not shown) consisting of N poles, and a peeling pole consisting of N poles in the developing sleeve 13a (Not shown) is provided.

  A scoop blade 18 for regulating the thickness of the developer carried on the developing roller 13 is attached to the developing container 10 along the longitudinal direction of the developing roller 13 (see FIGS. 7 and 8). The blade cutting blade 18 is positioned upstream of the opposing position of the developing roller 13 and the photosensitive drum 43 in the rotational direction of the developing roller 13. Then, a slight gap is provided between the tip of the cutting blade 18 and the surface of the developing roller 13.

  At the time of development, a high voltage power supply circuit (not shown) applies a DC bias voltage and an AC bias voltage to the developing roller 13. The toner in the developer is charged in the process of stirring and circulating the developer by the first transport member 11 and the second transport member 12. The second conveyance member 12 sends the developer in the second section 15 to the developing roller 13. Thereby, a magnetic brush (not shown) is formed on the developing roller 13. The thickness of the magnetic brush is regulated by the blade cutting blade 18, and the magnetic brush is conveyed to the opposing portion of the developing roller 13 and the photosensitive drum 43 by the rotation of the developing roller 13. The application of the DC bias voltage and the AC bias voltage causes the toner to fly from the developing roller 13 to the photosensitive drum 43, and the electrostatic latent image on the photosensitive drum 43 is developed.

(Flat cable 7)
Next, the coil 6 using the flat cable 7 according to the embodiment will be described with reference to FIG. 6, FIG. 9, and FIG. FIG. 9 is a view showing an example of the flat cable 7 according to the embodiment. FIG. 10 is a cross-sectional view of the flat cable 7 according to the embodiment.

  As shown in FIG. 9, the flat cable 7 used as the coil 6 is a cable in which a plurality of conducting wires 71 are arranged in a planar shape (strip shape). The conductors 71 of the flat cable 7 are arranged in parallel. Each conducting wire 71 is coated with an insulator 72 as shown in FIG. Adjacent conducting wires 71 are connected by the insulator 72 so as to be parallel to each other (in FIG. 9, the conducting wires 71 in the insulator 72 are shown by broken lines). Moreover, the end 71a of each conducting wire 71 of the flat cable 7 is exposed as a terminal. For example, the film of the insulator 72 on one side of the flat cable 7 is peeled off. In addition, flat cable 7 itself can divert what is distribute | circulated generally.

  As described above, at both end portions of the first section 14 and the second section 15 in the longitudinal direction of the developing container 10, the communication portions 17 connecting the both ends of the first section 14 and the second section 15 are provided. On the other hand, as shown in FIG. 6, a gap 16 is provided on the inner side in the longitudinal direction than the communication part 17 and between the first section 14 and the second section 15.

  The first section 14 between the communication portions 17 has a cylindrical shape due to the gap 16. In other words, a portion of the first section 14 which is adjacent to the gap 16 in the first section 14 passes through the first transport member 11 and the developer, and has a tubular shape capable of winding the flat cable 7. . The flat cable 7 can be inserted into the gap 16, and the flat cable 7 can be wound in the first section 14 a plurality of times so that the conducting wire 71 included in the flat cable 7 is orthogonal to the developer transport direction. Thereby, the flat cable 7 can be made to function as the coil 6 which makes a developer (magnetic carrier) a core. In addition, in FIG. 6, the example which provides the clearance gap 16 over between two communication parts 17 is shown. However, the length in the longitudinal direction of the gap 16 may be long enough to insert the flat cable 7 therethrough.

  In addition, since the flat cable 7 is wound in a plurality of turns, a sufficiently large inductance value can be obtained even if the width in the direction perpendicular to the direction of the conductive wire 71 of the flat cable 7 is narrow (even the flat cable 7 containing a small number of conductive wires 71). The coil 6 which it has can be obtained. Therefore, the width of the flat cable 7 in the direction perpendicular to the direction of the conducting wire 71 may be one pitch or several pitches of the blades 11 a of the first conveyance member 11. In addition, the width of the flat cable 7 may be determined in consideration of the inductance to be obtained and the number of turns.

(Winding of flat cable 7)
Next, winding of the flat cable 7 in the developing device 1 according to the embodiment will be described with reference to FIGS. 11 to 14. FIG. 11 is a view showing an example of a state in which the flat cable 7 according to the embodiment is wound as the coil 6. FIG. 12 is a view showing an example of the cable substrate 8 according to the embodiment. Drawing 13 is a figure showing an example of connector 9 provided in cable substrate 8 concerning an embodiment. FIG. 14 is a view showing an example of the hook 84 according to the embodiment.

  FIG. 11 shows an example in which one flat cable 7 is passed through the gap 16 and the flat cable 7 is wound around the cylindrical portion of the first section 14 of the developing device 1 multiple times. The developing device 1 is provided with a cable substrate 8 for fixing the flat cable 7 and using the flat cable 7 as the coil 6. FIG. 11 shows an example in which the cable substrate 8 is provided below the first section 14 of the developing device 1.

  The end 71a of each conducting wire 71 is exposed at each end of each flat cable 7 (see FIG. 9). The cable substrate 8 is provided with a plurality of connectors 9 (9A, 9B). As shown in FIG. 11, in the case where one flat cable 7 is wound around the first section 14 a plurality of turns, two connectors 9A and 9B are provided. One end of the flat cable 7 is inserted into one connector 9A, and the other end of the flat cable 7 is inserted into the other connector 9B.

  As shown in FIG. 12, the connector 9 (9A, 9B) includes a plurality of connector terminals 91. The connector terminals 91 are provided in the same number and at the same intervals as the conductors 71 of the flat cable 7. When the flat cable 7 is inserted, the end 71 a of one conducting wire 71 contacts one connector terminal 91.

  Each connector 9 is provided only on one side of the cable substrate 8. In other words, the connectors 9A and 9B are provided on the same surface of the cable substrate 8. The surface on which the connectors 9A and 9B are not provided is in contact with the wall surface of the first section 14 of the developing device 1. Thereby, the cable substrate 8 and the first section 14 can be brought close to each other as much as possible.

  FIG. 12 shows an example of a cable substrate 8 used when one flat cable 7 is used as the coil 6. Specifically, the cable substrate 8 is provided with a substrate hole 81 through which one flat cable 7 wound around the first section 14 a plurality of times passes, two connectors 9A and 9B, and a pattern 82. As shown in FIG. 12, the board hole 81 is provided so as to include the center of the plane of the cable board 8. The pattern 82 is provided to bypass the substrate hole 81.

  FIG. 11 shows an example in which one end of the flat cable 7 is inserted into the connector 9A closer to the gap 16 with the cable substrate 8 installed. Then, the other end of the flat cable 7 is passed through the gap 16 and the substrate hole 81, and the first section 14 is wound with the flat cable 7 in multiple turns as long as a desired inductance value is obtained. Thereafter, the other end of the flat cable 7 is passed through the board hole 81 and inserted into the connector 9B which is far from the gap 16.

  The connector 9 </ b> A closer to the gap 16 is oriented such that the insertion hole is in the lateral direction toward the gap 16. One end of the flat cable 7 is inserted into the connector 9A from the gap 16 side. The flat cable 7 does not need to be bent significantly when wound around the first section 14 as compared with the case where the insertion port of the connector 9A is directed downward, and the flat cable 7 is less likely to come off. Further, the connector 9A can wind the flat cable 7 so as to approach the magnetic carrier as much as possible by orienting the insertion port sideways and toward the gap 16.

  Each connector 9 includes a lock portion 92 that holds and locks the inserted flat cable 7 so that the inserted flat cable 7 does not come off (do not come off). There is no particular limitation on the locking method. In FIG. 13, the connector 9 in which the terminal is provided in contact with the end 71a of the conducting wire 71 of the flat cable 7 is illustrated. And in FIG. 13, the flat cable 7 is inserted and the type which operates the lock part 92 (opening / closing part, lever) and locks the flat cable 7 is illustrated. The cable substrate 8 and the flat cable 7 may be connected by attaching a header to each end of the flat cable 7 and arranging a socket type connector 9 into which the header is inserted to the cable substrate 8. In this case, the header and the socket are provided with a mechanism for locking the flat cable 7 so as not to come off.

  As shown in FIG. 12, on the cable substrate 8, there is provided a pattern 82 in which the flat cable 7 is wired to form one coil 6 for winding the first section 14 (connector terminals 91 of one connector 9 and the other connector A plurality of signal lines connecting the nine connector terminals 91 are provided. In other words, the pattern 82 shifts and connects the end portions 71 a of the conductors 71 of the flat cable 7 connected to the connectors 9 one by one so that the flat cable 7 becomes one coil 6. In FIG. 12, the pattern 82 (signal line) is indicated by a thick line.

  Specifically, one signal line connects one connector terminal 91 of one connector 9 and one connector terminal 91 of the other connector 9. A pattern 82 in which signal lines are combined is wired. The connector terminal 91 with which the n-th conductor 71 at one end of the flat cable 7 contacts and the other end of the flat cable 7 in the arrangement direction of the conductors 71 of the flat cable 7 (in FIG. The pattern 82 is formed such that the connector terminals 91 in contact with the (n + 1) th conducting wire 71 are connected. When such a pattern 82 is formed, in one connector 9A, the connector terminal 91 in contact with the last conductor 71 of the flat cable 7 and in the other connector 9B, is in contact with the first conductor 71 of the flat cable 7 The connector terminal 91 functions as a coil terminal 83 of the toner concentration sensor 5. The current input from one coil terminal 83 passes through all the conductors 71 of the pattern 82 and the flat cable 7 and is output from the other coil terminal 83.

  A connector terminal 91 in contact with the n-th conductor 71 at one end of the flat cable 7 in the direction in which the conductors 71 of the flat cable 7 are arranged, and an n-1th conductor 71 at the other end of the flat cable 7 The pattern 82 may be formed such that the connector terminals 91 in contact with each other are connected. When such a pattern 82 is formed, in one connector 9A, a connector terminal 91 in contact with the lead wire 71 of the flat cable 7 and in the other connector 9B, contact the rearmost lead wire 71 of the flat cable 7 The connector terminal 91 functions as a coil terminal 83 of the toner concentration sensor 5.

  The period (resonance frequency) of the output signal of the toner concentration sensor 5 is affected by the distance between the magnetic carrier and the flat cable 7. Depending on the condition of the flat cable 7 being wound, the output signal of the toner density sensor 5 may vary and an error may occur. For example, in the state in which the flat cable 7 is slack and in the state in which the flat cable 7 is tightly wound, the output signal of the toner density sensor 5 may be different even if the same developer is detected. The state in which the flat cable 7 is wound in any developing device 1 is preferably the same.

  Therefore, as shown in FIG. 12 and FIG. 14, the developing device 1 is provided with a hook 84. The other end of the flat cable 7 is inserted into the connector 9B while being hooked on the hook 84. In other words, of the flat cable 7 wound around the first section 14 a plurality of times, the portion of the flat cable 7 at the outermost peripheral portion is hooked on the hook 84. The hook 84 is, for example, an L-shaped member. The end of the flat cable 7 in the direction perpendicular to the conductor 71 is hooked on the top of the hook 84.

  In the example of FIG. 12, the portion of the flat cable 7 between the other end and the substrate hole 81 is hooked on the hook 84. The flat cable 7 is tensioned by the hooks 84. Among the flat cables 7 wound in the first section 14, the inner flat cable 7 can be prevented from loosening. Therefore, most of the flat cable 7 can be positioned as close to the magnetic carrier as possible.

(Modification)
Next, a modification is described using FIGS. 15 and 16. FIG. 15 is a view showing an example of winding the flat cable 7 around the first section 14 in the modification. FIG. 16 is a view showing an example of a cable substrate 8 according to a modification.

  In the above description, an example in which one flat cable 7 is wound around the first section 14 (tube portion) a plurality of turns has been described. In the modification, an example in which a plurality of flat cables 7 are prepared and each flat cable 7 is wound around the first section 14 will be described.

  FIG. 15 shows an example in which two flat cables 7 are prepared, and two flat cables 7 are stacked and wound around the first section 14. A plurality of flat cables 7 are prepared, and the plurality of flat cables 7 are overlapped and wound to form a coil 6 for winding the first section 14 a plurality of times. In a modification, the cable substrate 8 is provided with connectors 9 (connectors 9 (9a, 9b, 9c, 9d) twice as many as the number of flat cables 7. Each connector 9 has an end of one of the flat cables 7) In the modification, the connector 9 may be of a lock type.

  Also in the modification, a pattern 82 (a plurality of signal lines connecting a connector terminal 91 of one connector 9 and a connector terminal 91 of another connector 9) is provided on the cable substrate 8. In the modification, a pattern 82 is provided so as to shift and connect the conductors 71 of the respective ends of the same flat cable 7 among the flat cables 7 connected to the respective connectors 9 one by one. Thus, the ends 71a of the conductors 71 of the flat cable 7 are connected to each other so as to form one coil 6. Furthermore, the coil 6 of each flat cable 7 is connected in series, and a signal line for forming one coil 6 is also included in the pattern 82.

  Four connectors 9 (connectors 9 (9a, 9b, 9c, 9d) are provided on the cable substrate 8 in Fig. 16. Of the four connectors 9a, 9b, 9c, 9d, the two inner connectors 9a, 9b are provided. In the two flat cables 7, the end of the flat cable 7 wound inward is inserted into the two flat cables 7. In the two outer connectors 9c and 9d, the two flat cables 7 are wound outward. The flat cable 7 is inserted.

  In FIG. 16, the pattern 82 formed on the surface of the cable substrate 8 on which the connectors 9a, 9b, 9c, 9d are provided is shown by a solid line. Moreover, in FIG. 16, the pattern 82 formed in the surface of the back side of the surface in which connectors 9a, 9b, 9c, and 9d are provided among the cable board | substrates 8 is shown in figure by the broken line.

  For the inner two connectors 9a and 9b, a pattern 82 is provided to connect one connector terminal 91 of one connector 9a and the connector terminal 91 of the other connector 9b. Specifically, the connector terminal 91 in contact with the n-th conductor 71 of the flat cable 7 connected to one (lower) connector 9a in the arrangement direction of the conductors 71 of the flat cable 7 with the left side at the top of FIG. The pattern 82 is formed to be connected to the connector terminal 91 in contact with the (n + 1) th conductor 71 of the flat cable 7 connected to the other (upper) connector 9b. By the pattern 82 thus formed, the conductors 71 of the inner flat cable 7 are connected so as to form one coil 6.

  For the two outer connectors 9c and 9d, patterns 82 (each signal line) are provided to connect one terminal of one connector 9c and one terminal of the other connector 9d. The connector terminal 91 in contact with the nth conductor 71 of the flat cable 7 connected to one (upper) connector 9c in the arranging direction of the conductors 71 of the flat cable 7 with the left side at the top in FIG. The pattern 82 is formed such that the connector terminal 91 in contact with the (n + 1) th conducting wire 71 of the flat cable 7 connected to the connector 9d of FIG. By the pattern 82 formed in this manner, the conductors 71 are connected to each other so that the outer flat cable 7 also becomes one coil 6.

  In order to serially connect the coil 6 of the flat cable 7 wound inward and the coil 6 of the flat cable 7 wound outward, in the example of FIG. 16, the top of the upper connector 9B of the two inner connectors 9 A pattern 82 is formed to connect the connector terminal 91 on the side and the connector terminal 91 on the top side of the lower connector 9 d of the two outer connectors 9.

  As a result, of the inner two connectors 9, the rearmost connector terminal 91 of the lower connector 9a and the rearmost connector terminal 91 of the upper connector 9c of the outer two connectors 9 constitute one toner. The coil terminal 83 of the concentration sensor 5 is used. Also in the modification, the current input from one coil terminal 83 passes through all the conductors 71 of the pattern 82 and the flat cable 7 and is output from the other coil terminal 83.

  Thus, the developing device 1 according to the embodiment includes the developing container 10, the first conveying member 11, the second conveying member 12, the developing roller 13, the toner concentration sensor 5, the flat cable 7, and the cable substrate 8. The developer container 10 contains a developer containing a carrier and a toner, and is divided into a first section 14 and a second section 15, and both end portions of the first section 14 and the second section 15 in the longitudinal direction are first A communication portion 17 connecting the end portions of the section 14 and the second section 15 is provided, and a gap 16 is provided inside the respective communication sections 17 in the longitudinal direction and between the first section 14 and the second section 15 . The first transport member 11 is provided in the first section 14 and transports the developer while stirring the developer along the longitudinal direction of the developing container 10. The second conveyance member 12 is provided in the second section 15 and conveys the developer in the developing container 10 while stirring the developer in the opposite direction to the first conveyance member 11. The developing roller 13 is rotatably supported by the developing container 10 and carries a developer to be supplied to an image carrier on which an electrostatic latent image is formed. The toner concentration sensor 5 is for detecting the toner concentration in the developer, and includes a coil 6. The flat cable 7 is wound around the gap 16 in a plurality of turns as a coil 6 in a part of the first section 14. The cable substrate 8 is provided with a plurality of connectors 9 and the patterns 82 are wired. One end of the flat cable 7 is inserted into the connector 9, and a plurality of connector terminals 91 are provided in contact with the end 71 a of each wire 71 of the flat cable 7. The cable substrate 8 has the conductors 71 at one end of the flat cable 7 and the conductors at the other end of the flat cable 7 so that the flat cable 7 connected to the connector 9 forms one coil 6 that winds the first section 14. 71 includes a pattern 82 wired to connect 71.

  As a result, even if the flat cable 7 having a narrow width (the length in the direction perpendicular to the direction of the conductive wire 71 is short, and the number of conductive wires 71 included is relatively small) is used, sufficient inductance for the coil 6 of the flat cable 7 It can have a value. Further, by selecting the number of windings in the first section 14, the inductance value of the coil 6 of the flat cable 7 can be set to a desired value.

  Moreover, since it is not necessary to use the wide flat cable 7, the range which should not provide a metal member can be made small. Therefore, the design restrictions of the image forming apparatus including the developing device 1 and the developing device 1 can be reduced. Further, the coil 6 can be prepared inexpensively and easily as compared with the case where the multilayer cable board 8 including a plurality of coil 6 patterns 82 is used.

  Furthermore, since the coil 6 can be provided so that the developer passes through the inside of the substantially cylindrical coil 6 while bringing the entire coil 6 close to the developer, the sensitivity of the toner concentration sensor 5 can be enhanced to make the toner concentration accurate. It can be detected. Accordingly, it is possible to provide the developing device 1 capable of maintaining the ratio of the magnetic carrier of the developer to the toner accurately and accurately. Therefore, the developing device 1 with high image quality can be provided.

  Further, the cable substrate 8 is provided with a substrate hole 81 through which one flat cable 7 wound around the first section 14 a plurality of times passes, and two connectors 9 (9A, 9B). The patterns 82 are wired such that the ends 71a of the conductors 71 of the flat cable 7 connected to the connectors 9 (9A, 9B) are shifted one by one and connected. Thus, one flat cable 7 can be wound around the first section 14 a plurality of times through the substrate hole 81, and the coil 6 having a desired inductance value can be obtained. Further, the number of connectors 9 provided on the cable substrate 8 can be minimized (two), and the manufacturing cost of the cable substrate 8 can be reduced.

  Also, the board hole 81 is provided so as to include the center of the plane of the cable board 8. The pattern 82 is provided to bypass the substrate hole 81. Thereby, the flat cable 7 can be wound around the first section 14 in a well-balanced manner. Further, since the pattern 82 is provided so as to bypass the substrate hole 81, even if the substrate hole 81 is provided, the respective conducting wires 71 at both ends of the flat cable 7 can be connected so as to form one coil 6. .

  Even if the ratio of the magnetic carrier and the toner of the developer is the same, the output signal of the toner density sensor 5 changes depending on the distance between the coil 6 and the developer. Therefore, of the flat cables 7 wound around the first section 14 a plurality of times, the flat cable 7 at the outermost peripheral portion is hooked and tension is applied so that the flat cable 7 wound a plurality of times around the first section 14 does not loosen. A hook 84 is provided. This can prevent the flat cable 7 wound around the first section 14 from bulging or loosening. In other words, the flat cable 7 can be fixed at a fixed position. Since the position of the coil 6 is constant, it is possible to accurately eliminate variations and errors in the output signal of the toner density sensor 5.

  Further, in the developing device 1 according to the modification, the cable substrate 8 is overlapped and wound to form a plurality of flat cables 7 that wind the first section 14 a plurality of times and a connector 9 twice the number of flat cables 7. Including. The pattern 82 connects the conductors 71 of the respective ends of the same flat cable 7 among the flat cables 7 connected to the connector 9 while shifting them one by one, and forms a single coil 6. They are wired to connect each other. Thus, the coil 6 having a desired inductance value can be obtained by stacking a plurality of flat cables 7 and winding each flat cable 7 once in the first section 14. Further, even if flat cables 7 having a narrow width (the length in the direction perpendicular to the direction of the conducting wire 71 is short) are stacked, the coil 6 having a desired inductance value can be obtained.

  Also, all the connectors 9 (connectors 9 (9A, 9B) or connectors 9 (9a, 9b, 9c, 9d) are provided on the same surface of the cable substrate 8. This makes the cable substrate 8 smaller. Also, the cable substrate 8 can be simplified.

  Also, the connectors (connectors 9 (9A, 9B), a, b, c, d) include lock portions 92 that lock the inserted flat cable 7 therebetween. Thereby, even if force is applied to the flat cable 7 in the direction of coming out of the connector 9, it is possible to prevent the flat cable 7 from coming off the connector 9.

  Further, since the printer 100 (image forming apparatus) includes the developing device 1 capable of keeping the ratio of the magnetic carrier and the toner substantially constant all the time, the image forming apparatus capable of maintaining the high image quality can be provided.

  As mentioned above, although embodiment of this invention was described, the range of this invention is not limited to this, A various change can be added and implemented in the range which does not deviate from the main point of invention.

  The present invention can be used for a developing device or an image forming apparatus that detects a toner concentration using a two-component developer containing a magnetic carrier and a toner and using a coil using a flat cable.

DESCRIPTION OF SYMBOLS 1 developing device 10 developing container 11 1st conveyance member 12 2nd conveyance member 13 development roller 14 1st division 15 2nd division 16 gap 17 communication part 43 photosensitive drum (image carrier)
Reference Signs List 5 toner density sensor 6 coil 7 flat cable 71 conductor 8 cable board 82 pattern 81 board hole 84 hook 9 connector 9A connector 9B connector 9a connector 9b connector 9c connector 9d connector 91 connector terminal 92 lock unit 100 printer (image forming apparatus)

Claims (8)

A developer containing a carrier and a toner is accommodated and divided into a first section and a second section, and both end portions in the longitudinal direction of the first section and the second section are the first section and the second section. And a developing container having a communication portion connecting the end portions of each of the first and second sections, and a gap is provided between the first section and the second section on the inner side in the longitudinal direction with respect to the respective communication sections.
A first conveyance member provided in the first section for stirring and conveying the developer along the longitudinal direction of the developing container;
A second conveyance member provided in the second section and stirring and conveying the developer in the developing container in a direction opposite to the first conveyance member;
A developing roller rotatably supported by the developing container and carrying a developer to be supplied to an image carrier on which an electrostatic latent image is formed;
A toner concentration sensor, including a coil, for detecting the toner concentration in the developer;
A flat cable wound as a plurality of turns around the part of the first section through the gap;
Including a cable board provided with a plurality of connectors and wired patterns;
In the connector, one of the ends of the flat cable is inserted, and a plurality of connector terminals in contact with the ends of the respective conductors of the flat cable are provided.
The cable substrate includes the conductors at one end of the flat cable and the conductors at the other end of the flat cable so that the flat cable connected to the connector forms one coil of the first section. A developing device comprising the pattern wired to be connected. The cable substrate is provided with a substrate hole through which one flat cable wound around the first section passes a plurality of times, and two connectors.
2. The developing device according to claim 1, wherein the pattern is wired so as to shift and connect one end of each lead of the flat cable connected to each of the connectors. The substrate hole is provided so as to include the center of the plane of the cable substrate,
The developing device according to claim 2, wherein the pattern is provided to bypass the substrate hole.   A hook that is hooked on the flat cable at the outermost peripheral portion of the flat cable wound around the first section a plurality of times and applies tension to prevent the flat cable wound around the first section from loosening a plurality of times The developing device according to claim 2, wherein the developing device is provided. The cable substrate includes a plurality of flat cables wound in a plurality of turns around the first section by being overlapped and wound, and the connectors twice as many as the number of flat cables.
The pattern connects the flat cables together so as to form a single coil while shifting and connecting one end of each wire of the same flat cable among the flat cables connected to the connector. The developing device according to claim 1, wherein the developing device is wired.   The developing device according to any one of claims 1 to 5, wherein all the connectors are provided on the same surface of the cable substrate.   The developing device according to any one of claims 1 to 6, wherein the connector includes a lock portion which holds and locks the flat cable inserted.   An image forming apparatus comprising the developing device according to any one of claims 1 to 7.

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